This report describes a man who died following a gun-shot wound which entered the right atrium and exited the right ventricle without entering the cardiac septa or the left side of the heart. At necropsy, the left atrial appendage was found to be inverted and invaginated into the mitral orifice. The invagination of the left atrial appendage is viewed as anatomic evidence that a negative left ventricular pressure was created as the left ventricular volume rapidly fell from right-sided cardiac exsanguination.